The present invention is related to a printed wiring board, and particularly to the reinforcement of printed circuits in the work such as the outer shaping work of the printed wiring board by a press die.
Typically, a printed wiring board of the prior art has printed circuits provided one or both sides of a substrate.
In addition, when forming printed circuits in the printed wiring board of the above described construction, an edge of 0.4 mm is usually left along the outer periphery of the substrate and a pattern is formed inside thereof insure electrical reliability and safety. The requirement depends on the use of the board.
Further, the thickness of the substrate is usually 1.6 mm, and consists of, a paper phenol, glass epoxy or composite epoxy material. Outer shaping work is performed monolithically by a press-cutting method using a press die.
Since the material of the substrate is hard when it is a glass epoxy or composite epoxy material, the cutting by a press die has some difficulty, but such material is generally used in view of productivity and cost.